Dachsous encodes a member of the cadherin superfamily that controls imaginai disc morphogenesis in Drosophila

Mutations in the dachsous gene of Drosophila lead to striking defects in the morphogenesis of the thorax, legs, and wings. The dachsous gene has been cloned and shown to encode a huge transmembrane protein that is a member of the cadherin superfamily, similar to the fat gene reported previously. Both the Dachsous and Fat proteins contain large tandem arrays of cadherin domains-27 and 34, respectively - as compared with 4 cadherin domains in classic vertebrate cadherins. In addition, Dachsous and Fat each has a cytoplasmic domain with sequence similarity to the cytoplasmic β-catenin-binding domain of classic vertebrate cadherins. The dachsous gene is expressed in the ectoderm of embryos, whereas its expression in larvae is restricted to imaginai discs and specific regions of the brain. The phenotypes of, and genetic interactions between dachsous and fat are consistent with a model in which cell proliferation and morphogenesis of imaginai structures depends on the coupled equilibria between homo- and heterophilic interactions of the Dachsous and Fat cadherin proteins.